Method and system for controlling temperature of an internal combustion engine exhaust gas aftertreatment device

Claim 1

A method for controlling an internal combustion engine, the engine being a multi-cylinder engine with a first group of cylinders coupled to an exhaust aftertreatment device and a second group of cylinders being decoupled from the exhaust aftertreatment device, the method comprising: operating the first group of cylinders at a first operating condition; operating the second group of cylinders at a second operating condition, wherein the first operating condition generates a higher torque than said second operating condition and said second operating condition provides positive torque; and commanding an injector disposed in an engine exhaust to supply reductant to the exhaust aftertreatment device when a temperature in the exhaust aftertreatment device exceeds a threshold temperature when the first group of cylinders a operating at said first operating condition.

Claim 2

A method for controlling an internal combustion engine, the engine being a multi-cylinder engine with a first group of cylinders coupled to an exhaust aftertreatment device and a second group of cylinders being decoupled from the exhaust aftertreatment device, the method comprising: operating the first group of cylinders at a first operating condition; operating the second group of cylinders at a second operating condition, wherein the first operating condition generates a higher torque than said second operating condition and said second operating condition provides positive torque; and commanding an injector disposed in an engine exhaust to supply reductant to the exhaust aftertreatment device when a temperature in the exhaust aftertreatment device exceeds a threshold temperature when the first group of cylinders a operating at said first operating condition.

Claim 6

A method for controlling an internal combustion engine, the engine being a multi-cylinder engine with a first group of cylinders coupled to at exhaust aftertreatment device and a second group of cylinders being decoupled from the exhaust aftertreatment device, the method comprising: operating the first group of cylinders at a first operating condition; operating the second group of cylinders at a second operating condition, wherein the first operating condition generates a higher torque then said second operating condition and said second operating condition provides positive torque; and commanding injectors disposed in engine cylinders of said first group of cylinders to inject fuel during an expansion stroke of the engine when a temperature in the exhaust aftertreatment device exceeds s threshold temperature and the first group of cylinders is operating at said first operating condition wherein said exhaust aftertreatment device is a lean NOx catalyst and said fuel injected during said expansion stroke is applied to said lean NOx catalyst.

Claim 7

A method for controlling an internal combustion engine, the engine being a multi-cylinder engine with a first group of cylinders coupled to at exhaust aftertreatment device and a second group of cylinders being decoupled from the exhaust aftertreatment device, the method comprising: operating the first group of cylinders at a first operating condition; operating the second group of cylinders at a second operating condition, wherein the first operating condition generates a higher torque then said second operating condition and said second operating condition provides positive torque; and commanding injectors disposed in engine cylinders of said first group of cylinders to inject fuel during an expansion stroke of the engine when a temperature in the exhaust aftertreatment device exceeds s threshold temperature and the first group of cylinders is operating at said first operating condition wherein said exhaust aftertreatment device is a lean NOx catalyst and said fuel injected during said expansion stroke is applied to said lean NOx catalyst.

Claim 8

A method for controlling an internal combustion engine, the engine being a multi-cylinder engine with a first group of cylinders coupled to an exhaust aftertreatment device and a second group of cylinders being decoupled from the exhaust aftertreatment device, the method comprising: operating the first group of cylinders at a first operating condition; operating the second group of cylinders at a second operating condition, wherein the first operating condition generates a higher torque than said second operating condition and said second operating condition provides positive torque wherein the exhaust aftertreatment device is a lean NOx catalyst and said operating steps are performed when a quantity of reductant stored in said lean NOx catalyst is less than a predetermined quantity.

Claim 9

A method for controlling an internal combustion engine, the engine being a multi-cylinder engine with a first group of cylinders coupled to an exhaust aftertreatment device and a second group of cylinders being decoupled from the exhaust aftertreatment device, the method comprising: operating the first group of cylinders at a first operating condition; operating the second group of cylinders at a second operating condition, wherein the first operating condition generates a higher torque than said second operating condition and said second operating condition provides positive torque wherein the exhaust aftertreatment device is a lean NOx catalyst and said operating steps are performed when a quantity of reductant stored in said lean NOx catalyst is less than a predetermined quantity.

Claim 12

A method for controlling torque in an internal combustion engine, the engine being a multi-cylinder engine with a first group of cylinders coupled to a first exhaust aftertreatment device and a second group of cylinders coupled to a second exhaust aftertreatment device, the engine having first and second injectors disposed in an engine exhaust, the injectors being capable of supplying reductant to the first and second aftertreatment devices, respectively, the method comprising: operating the first group of cylinders at a first operating condition; operating the second group of cylinders at a second operating condition, wherein said first operating condition generates a higher torque than said second operating condition; and commanding the first injector to provide reductant to the first aftertreatment device when temperature in the first aftertreatment device exceeds a threshold temperature.

Claim 13

A method for controlling torque in an internal combustion engine, the engine being a multi-cylinder engine with a first group of cylinders coupled to a first exhaust aftertreatment device and a second group of cylinders coupled to a second exhaust aftertreatment device, the engine having first and second injectors disposed in an engine exhaust, the injectors being capable of supplying reductant to the first and second aftertreatment devices, respectively, the method comprising: operating the first group of cylinders at a first operating condition; operating the second group of cylinders at a second operating condition, wherein said first operating condition generates a higher torque than said second operating condition; and commanding the first injector to provide reductant to the first aftertreatment device when temperature in the first aftertreatment device exceeds a threshold temperature.

Claim 20

A system for controlling a multi-cylinder internal combustion engine, the engine having a first group of cylinders and a second group of cylinders wherein the first and second groups of cylinders ate mutually exclusive, comprising: a first exhaust manifold coupled to the first group of cylinders; an exhaust aftertreatment device coupled to the exhaust manifold; an electronic control unit coupled to the engine, said electronic control unit operating the first group of cylinders at a first operating condition and operating the second group of cylinders at a second operating condition, wherein said first and second operating conditions provide positive and unequal torques; and a reductant injector located upstream of said exhaust aftertreatment device, said injector being coupled to said electronic control unit wherein said electronic control unit commands said injector to inject reductant when a temperature in said first aftertreatment device exceeds a threshold temperature.

Claim 21

A system for controlling a multi-cylinder internal combustion engine, the engine having a first group of cylinders and a second group of cylinders wherein the first and second groups of cylinders ate mutually exclusive, comprising: a first exhaust manifold coupled to the first group of cylinders; an exhaust aftertreatment device coupled to the exhaust manifold; an electronic control unit coupled to the engine, said electronic control unit operating the first group of cylinders at a first operating condition and operating the second group of cylinders at a second operating condition, wherein said first and second operating conditions provide positive and unequal torques; and a reductant injector located upstream of said exhaust aftertreatment device, said injector being coupled to said electronic control unit wherein said electronic control unit commands said injector to inject reductant when a temperature in said first aftertreatment device exceeds a threshold temperature.

Claim 24

A system for controlling a multi-cylinder internal combustion engine, the engine having a first group of cylinders and a second group of cylinders wherein the first and second groups of cylinders are mutually exclusive, comprising: a first exhaust manifold coupled to the first group of cylinders; an exhaust aftertreatment device coupled to the exhaust manifold; and an electronic control unit coupled to the engine, said electronic control unit operating the first group of cylinders at a first operating condition and operating the second group of cylinders at a second operating condition, wherein said first and second operating conditions provide positive and unequal torques, said engine is a lean burn gasoline engine, said exhaust aftertreatment device is a lean NOx trap, and said first operating conditions cause temperature in said lean NOx trap to be lower than an upper operating temperature of said lean NOx trap.

Claim 25

A system for controlling a multi-cylinder internal combustion engine, the engine having a first group of cylinders and a second group of cylinders wherein the first and second groups of cylinders are mutually exclusive, comprising: a first exhaust manifold coupled to the first group of cylinders; an exhaust aftertreatment device coupled to the exhaust manifold; and an electronic control unit coupled to the engine, said electronic control unit operating the first group of cylinders at a first operating condition and operating the second group of cylinders at a second operating condition, wherein said first and second operating conditions provide positive and unequal torques, said engine is a lean burn gasoline engine, said exhaust aftertreatment device is a lean NOx trap, and said first operating conditions cause temperature in said lean NOx trap to be lower than an upper operating temperature of said lean NOx trap.

Claim 27

A method for controlling a diesel engine, the engine being a multi-cylinder engine having a first group of cylinders coupled to a first lean NOx catalyst and a second group of cylinders coupled to a second lean NOx catalyst wherein said first and second groups of cylinders are mutually exclusive, the method comprising: discontinuing fuel delivery to the first group of cylinders; operating the second group of cylinders at an operating condition providing a driver demanded torque with the fuel delivery to the first group of cylinders being discontinued; and supplying reductant to the first lean NOx catalyst the second group of cylinders being at an operating condition providing a driver demanded torque.

Claim 28

A method for controlling a diesel engine, the engine being a multi-cylinder engine having a first group of cylinders coupled to a first lean NOx catalyst and a second group of cylinders coupled to a second lean NOx catalyst wherein said first and second groups of cylinders are mutually exclusive, the method comprising: discontinuing fuel delivery to the first group of cylinders; operating the second group of cylinders at an operating condition providing a driver demanded torque with the fuel delivery to the first group of cylinders being discontinued; and supplying reductant to the first lean NOx catalyst the second group of cylinders being at an operating condition providing a driver demanded torque.

Claim 30

A method for controlling a diesel engine, the engine being a multi-cylinder engine having a first group of cylinders coupled to a lean NOx catalyst, a second group of cylinders not coupled to the lean NOx catalyst, and a reductant injector disposed in an engine exhaust coupled to the first group of cylinders for providing reductant to the lean NOx catalyst, the method comprising: operating said first and second groups of cylinders according to a first set of operating conditions when a driver demanded torque is greater than a predetermined torque; and operating said first and second group of cylinders according to a second set of operating conditions when said driver demanded torque is less than said predetermined torque wherein said first and second sets of operating conditions are such that a torque provided by said first group of cylinders is different than a torque provided by said second group of cylinders and said first set of operating conditions, further comprises: operating the first group of cylinders at a first operating point; operating the second group of cylinders at a second operating point, wherein said first operating point generates a higher torque than said second operating point and said second operating point provides positive torque; and commanding said injector to provide reductant to the lean NOx catalyst when a temperature within the lean NOx catalyst exceeds a predetermined temperature.

Claim 31

A method for controlling a diesel engine, the engine being a multi-cylinder engine having a first group of cylinders coupled to a lean NOx catalyst, a second group of cylinders not coupled to the lean NOx catalyst, and a reductant injector disposed in an engine exhaust coupled to the first group of cylinders for providing reductant to the lean NOx catalyst, the method comprising: operating said first and second groups of cylinders according to a first set of operating conditions when a driver demanded torque is greater than a predetermined torque; and operating said first and second group of cylinders according to a second set of operating conditions when said driver demanded torque is less than said predetermined torque wherein said first and second sets of operating conditions are such that a torque provided by said first group of cylinders is different than a torque provided by said second group of cylinders and said first set of operating conditions, further comprises: operating the first group of cylinders at a first operating point; operating the second group of cylinders at a second operating point, wherein said first operating point generates a higher torque than said second operating point and said second operating point provides positive torque; and commanding said injector to provide reductant to the lean NOx catalyst when a temperature within the lean NOx catalyst exceeds a predetermined temperature.

Claim 33

A method for controlling a diesel engine, the engine being a multi-cylinder engine having a first group of cylinder, coupled to a lean NOx catalyst, a second group of cylinders not coupled to the lean NOx catalyst, and a reductant injector disposed in an engine exhaust coupled to the first group of cylinders for providing reductant to the lean NOx catalyst, the method comprising: operating said first and second groups of cylinder, according to a first set of operating conditions when a driver demanded torque is greater than a predetermined torque; and operating said first and second group of cylinders according to a second set of operating conditions when said driver demanded torque is less than said predetermined torque wherein said first and second sets of operating conditions are such that a torque provided by said first group of cylinders is different than a torque provided by said second group of cylinders, and said second set of operating conditions further comprises: discontinuing fuel delivery to the first group of cylinder; operating the second group of cylinders at an operating point which causes the engine to provide said operator demanded torque with fuel delivery to the first group of cylinders being discontinued; and commanding said injector to provide reductant to the lean NOx catalyst while operating the second group of cylinders at an operating point which causes the engine to provide said operator demanded torque with fuel delivery to the first group of cylinders being discontinued.

Claim 34

A method for controlling a diesel engine, the engine being a multi-cylinder engine having a first group of cylinder, coupled to a lean NOx catalyst, a second group of cylinders not coupled to the lean NOx catalyst, and a reductant injector disposed in an engine exhaust coupled to the first group of cylinders for providing reductant to the lean NOx catalyst, the method comprising: operating said first and second groups of cylinder, according to a first set of operating conditions when a driver demanded torque is greater than a predetermined torque; and operating said first and second group of cylinders according to a second set of operating conditions when said driver demanded torque is less than said predetermined torque wherein said first and second sets of operating conditions are such that a torque provided by said first group of cylinders is different than a torque provided by said second group of cylinders, and said second set of operating conditions further comprises: discontinuing fuel delivery to the first group of cylinder; operating the second group of cylinders at an operating point which causes the engine to provide said operator demanded torque with fuel delivery to the first group of cylinders being discontinued; and commanding said injector to provide reductant to the lean NOx catalyst while operating the second group of cylinders at an operating point which causes the engine to provide said operator demanded torque with fuel delivery to the first group of cylinders being discontinued.

Claim 35

A method for controlling temperature of an internal combustion engine exhaust gas aftertreatment device, such method comprising: operating a first portion of a plurality of engine cylinders at a first torque output and operating a second portion of said plurality of engine cylinders at a second torque output when temperature in the aftertreatment device is not within a desired temperature range, the overall torque output of the engine is substantially an operator demanded torque, and said first portion of cylinders is coupled to the aftertreatment device, said operator demanded torque is based on a portion of an accelerator pedal, and said second portion of engine cylinder is decoupled from the aftertreatment device.

Claim 36

A method for controlling temperature of an internal combustion engine exhaust gas aftertreatment device, such method comprising: operating a first portion of a plurality of engine cylinders at a first torque output and operating a second portion of said plurality of engine cylinders at a second torque output when temperature in the aftertreatment device is not within a desired temperature range, the overall torque output of the engine is substantially an operator demanded torque, and said first portion of cylinders is coupled to the aftertreatment device, said operator demanded torque is based on a portion of an accelerator pedal, and said second portion of engine cylinder is decoupled from the aftertreatment device.